Warning: This will fail on a channel with lots of names and/or long nicks.

Code:
menu * {
  Alphabetical Whois : who_is $input(Channel Name,e,,$iif($chan,$v1))
}
alias -l who_is {
  if !$nick($1,$me) {    echo -a Sorry you must be in $1  }
  else {
    var %a = 1, %b = $nick($1,0)
    while %a <= %b {
      set %alpha_nicks $addtok(%alpha_nicks,$nick($1,%a),32)
      inc %a
    }
    set %alpha_nicks $sorttok(%alpha_nicks,32)
  }
  var %a = 1, %b = $numtok(%alpha_nicks,32)
  while %a <= %b {
    .enable #alpha_whois
    whois $gettok(%alpha_nicks,%a,32)
    inc %a
  }
}
#alpha_whois off
raw *:*:{
  if $numeric == 318 {
    .disable #alpha_whois
  }
  elseif $int($calc($numeric / 100)) == 3 {
    echo -s $1-
  }
}
#alpha_whois end